Guralp Systems CMG-3TB, Руководство оператора

Страница: 30 / 78

CMG-3TB
fails to register ground movements, contact Güralp Systems.
15.Lock the sensor masses once more, tension the load bearing
cable and retract the hole lock arm.
16.Gently lower the sensor to the required depth. At approximately
20 m intervals, fix the signal cable to the load bearing cable
using metal clamps (nylon cable ties every 5 m may be sufficient
for shallow installations). This will ensure that the signal cable
does not become kinked or trapped within the borehole. Leave a
little slack on the signal cable each time, so that it does not bear
any weight. Too much slack, however, will cause the cable to
scrape against the borehole casing.
17.Fix the sensor system into the borehole using the hole lock arm
(see Section 2.6, page 22).
If you are installing a 3TB in a deep borehole, the weight of the
sensor will stretch the load bearing cable slightly. Remember to
allow for this when raising or lowering the cable in the
following steps.
18.Use the winch to drag the assembly up within the borehole for a
distance of 15 – 30 cm. This will ensure that the hole lock arm
and the skids or studs on the sonde keep the sensor package
vertical within the borehole. Do not drag too far, or you will
damage the contact points.
19.Lower the load bearing cable by around 30 cm to engage the
strain relief unit inside the borehole casing, and to provide some
slack in the cables.
20.Clamp the load bearing cable to the top of the borehole.
21.Tie the lifting and signal cables together above the strain relief
mechanism using tie wraps.
22.The sensor can now be levelled and unlocked ready for use.
30 Issue C